This invention relates to the control system for controlling a number of hydraulic functions on a agricultural machine towed by a tractor, the hydraulic functions being connected to the tractor hydraulic system and controlled by the tractor operator from the tractor.
Many pull-type or towed farm implements have a number of hydraulic motors or cylinders that control various functions on the implement, the hydraulic motors being connected by suitable conduits to hydraulic outlets on the tractor. For example, a pull-type baler is conventionally towed by a tractor and powered by the tractor power take-off system and includes a vertically adjustable header or pickup in addition to a swingable tongue, that is shiftable to position the baler behind the tractor for transport or into a field operating position, wherein the pickup is disposed outwardly of the tractor. Normally some means are provided for raising the pickup during transport of the machine or to clear obstacles in the field, and it is known to utilize a hydraulic cylinder so that the pickup can be raised via the cylinder without the operator leaving the tractor. Similarly, it is known to provide a hydraulic cylinder for controlling the position of the tongue so that the baler can be swung between its field and operating positions without the operator leaving the tractor seat.
Other agricultural machines such as mower conditioners have utilized separate hydraulic cylinders for raising the implement header and swinging the implement between transport and operating positions.
Most modern tractors used in agricultural field work have hydraulic systems that include at least one pair of hydraulic outlets on the rear of the tractor into which hydraulic lines on a towed implement can be plugged, a control valve conventionally being provided for each pair of outlets to control the flow of pressurized fluid to and from the hydraulic motor on the implement. Releasable couplings, such as shown in U.S. Pat. No. 3,140,102, are conventionally provided for connecting the implement hydraulic lines into the tractor outlets.
While most modern tractors, particularly the larger ones, are provided with up to three sets of outlets for controlling three separate hydraulic functions on the implement, many older or smaller tractors are provided with only one pair of outlets and are thus able to operate only one hydraulic function on the implement. Machines such as balers, as illustrated herein, or mower conditioners require less power than some of the other agricultural implements or tools, and are frequently operated by older or smaller tractors having only one pair of outlets, creating a problem if the implement has multiple hydraulic functions.
It is known in balers to provide mechanisms interconnecting their implement tongue and the pickup so that a single hydraulic cylinder can be utilized to raise the pickup and swing the tongue, although such devices are obviously more expensive and complicated than use of separate hydraulic cylinders.